Modern Physics Letters A

The ATLAS collaboration has recently reported excesses about 2.5 $\sigma$ at mass around 2 TeV in the diboson channels, which can be identified with new vector bosons as a hint for the new physics. It is shown that spontaneously broken conformal/scale symmetry prohibits new vector bosons decay to the Higgs, which is contrasted to the popular “equivalence theorem” valid only in a special limit not necessarily relevant to the 2 TeV mass. If the decay V $\to$ WH/ZH is not observed in the ongoing Run-II of the large hadron collider (LHC), then the 125 GeV Higgs can be a dilaton.

Compressed mass spectra are generally more difficult to identify than spectra with large splittings. In particular, gluino pair production with four high energy top or bottom quarks leaves a striking signature in a detector. However, if any of the mass splittings are compressed, the power of traditional techniques may deteriorate. Searches for direct stop/sbottom pair production can be recast as searches for gluinos in order to extend the sensitivitity. As a demonstration, we show that for $\tilde{g}\to t{\tilde{t}}_1$ and $m_{{\tilde{t}}_1}~m_{{\tilde{\chi }}_1^0}$, limits on the stop mass at 8 TeV can be extended by least 300 GeV for a 1.1 TeV gluino using a $pp\to {\tilde{t}}_1{\tilde{t}}_1$ search. At 13 TeV, the effective cross-section for the gluino mediated process is twice the direct stop pair production cross-section, suggesting that direct stop searches could be sensitive to discover new physics earlier than expected.

We present three independent methods to estimate the mass of the electroweak monopole. Our result strongly implies the existence of a genuine electroweak monopole of mass around 4–10 TeV, which could be detected by MoEDAL at present Large Hadron Collider (LHC). We emphasize that the discovery of the electroweak monopole should be the final test of the Standard Model.

The semiclassical effects of anti-evaporating black holes can be discussed in the framework of f(R) gravity. In particular, the Bousso–Hawking–Nojiri–Odinstov anti-evaporation instability of degenerate Schwarzschild–de Sitter black holes (the so-called Nariai spacetime) leads to a dynamical increasing of black hole horizon in f(R) gravity. This phenomenon causes the following transition: emitting marginally trapped surfaces (TS) become space-like surfaces before the effective Bekenstein–Hawking emission time. As a consequence, Bousso–Hawking thermal radiation cannot be emitted in an anti-evaporating Nariai black hole. Possible implications in cosmology and black hole physics are also discussed.

Recently, a phenomenological modification of ghost dark energy has been suggested and appropriate models of low redshift universe have been constructed. In this paper, we will consider a model of low redshift universe in General Relativity containing another model of varying ghost dark energy. In this model, an effective fluid is a radiation-like fluid in an early universe and evolves to quintessence dark energy in large scale universe. Cosmographic analysis of new model is performed and appropriate constraints on the parameters of the model are obtained. We have a look at suggested model via statefinder hierarchy in addition to thermodynamical description of it. We also study massless particle creation possibility in a radiation dominated universe of our cosmological model. According to our theoretical results, massless particle production is possible. To study particle creation, a straight analogy between quantization in Minkowski background and canonical quantization of a scalar field in curved dynamical backgrounds is taken into account.

In this paper, we derive the expression for spectral dimension using a modified diffusion equation in the $\kappa$-deformed spacetime. We start with the Beltrami–Laplace operator in the $\kappa$-Minkowski spacetime and obtain the deformed diffusion equation. From the solution of this deformed diffusion equation, we calculate the spectral dimension which depends on the deformation parameter “$a\left(=\frac{1}{\kappa }\right)$” and also on an integer “$l$”, apart from the topological dimension. Using this, we show that, for large diffusion times the spectral dimension approaches the usual topological dimension whereas spectral dimension diverges to $+\infty$ for $l\ge 0$ and $-\infty$ for $l<0$ at high energies.

In this paper, we consider the Klein–Gordon equation in a 3D charged rotating hairy black hole background to study behavior of a massive scalar field. In the general case, we find periodic-like behavior for the scalar field which may vanish at the black hole horizon or far from the black hole horizon. For the special cases of non-rotating or near horizon approximation, we find radial solution of Klein–Gordon equation in terms of hypergeometric and Kummer functions. Also for the case of uncharged black hole, we find numerical solution of the Klein–Gordon equation as periodic function which may enhance out of the black hole or vanish at horizon. We find allowed boundary conditions which may yield to the identical bosons described by scalar field.